Voltage-regulating means.



H. NEHLSEN. VOLTAGE REGULATING MEANS. APPLICATION FILED AUG.30, 1912.

4 4 9 Patented Jan. 13, 1914 2 SHEETS-SHEDT 1.

Fig.1.

Witnesses; Inventor-'2 (we f/M' Hermann T'lehlsen His a ttorngg H. NEHLSEN. VOLTAGE REGULATIRG MEANS. urmonmn mum we. ao, 1012.

v Patented Jan 13, 191i a sunms-annm 2.

Witnesses Inventor:

5M M Herann Tlehlsen',

19 Java His fitter-neg.

UNETEE STATES PATENT @FFZCE.

HERMANN IJEHLSEN, 0F NIEDERSCHGNHAUSEN, GERMANY, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORPORATIQN OF NEW YORK.

VOLTAGE REGULATING MEANS.

Specification of Letters Patent.

Patented Jan. 13, 1914.

T 0 all whom it may concern Be it known that I, HERMANN NEHLSEN, a subject of the Emperor of Germany, residing at Niederschonhausen, Germany, have invented certain new and useful Inr provements in V oltage- Regulating Means, of which the following is a specification. 4

My invention relates to voltage regulating means employing an induction regulator and a regulating transformer provided with taps, and the principal objects of my invention are to allow a simplification of the switching mechanism and often a reduction in the size of theregulator.

It is common to regulate an alternating current voltage by means of a regulating transformer by changing a terminal connec tion to different taps 'regularlyrspaced there in, using an induction potential regulator in parallel to the individual 'steps of the transformer to give asmooth, gradual change as the terminal is carried from one tap to another. The maximum voltage of the induction regulator is at least substantially equal to the voltage between two taps. Heretofore the line-terminal which is car-' ried from one tap to'another has been connected to one (electrical) end of the secondary windin of the induction regulator, the other end of that winding being con- 'nected to difierent taps in succession; in

other words the connections were such that the operating current traversed the entirelength of the secondary winding of the inducti'on regulator. In accordance with my invention I connect the movable line termithe center point, electrically, of the secondary Winding of the induction. regulator; the two ends thereof, then, are alternately connected to taps. But half the length of'the secondary winding of the regulator is at any one time traversed by the entire operating current and for some periods of time the entire secondary winding is traversed by but dne-half of the working current. By my invention therefore ,the induction regulator needs'to be of only one-half the rated capacity of the regulator -heretofore employed; the switching mechanism employed for making and break ing the required connections in the proper order, it has been found, may be much simplified. p In addition to the switching means for makingand breaking the connections between the ends of the regulator secondary and the taps, short circuiting the secondary Winding of the potential regulator portion of the apparatus, thus connecting the movable terminal direct to a tap, and avoiding the losses in the regulator. In numerous cases also, the whole arrangement allows the I use of a smaller regulator as is explained later,

The figures of the accompanying-drawing illustrate my invention. It will be understood that these illustrations are entirely diagrammatic and that the relative location of the parts and the independent control of the regulator and the different switches is not essential. i

No attempt has. been made to show a commercial form of switching mechanism; a highly developed form will probably be used witht-he regulating apparatus in practice.

Figure 1 illustrates my invention embodied in an induction regulator and a regulating transformer, the regulator being in the position where it is neither adding to nor subtracting from the electromotive force of the working part of the transformer and is short-circuited; Fig. -2 illustrates the same devices, that themovable line terminal is, electri .cally, half way between two taps; and Fig. 3 shows'myinvention applied to a polyphase voltage regulating means.

The transformer winding t is one of the windings of a regulating transformer T, to one end of which is connected a main or line terminal m. The movable main or line t-er-' minal n I connect to substantially the electrical center of the induction regulator secondary winding 8. The ends a and b of the secondary winding 8 of the potential regulator are to be connected in succession with the taps 1, 2, 3 and 4 of the winding t, as the movable line terminal 71. is carried along and the voltage varied. The primary winding of the induction regulator e may be connected to any suitable source of onr-' rent, as, for example, across the winding t as shown. The usual short-circuited second-- my 70 may be employed.

In the position of the regulator shown in +ig.. 1', the regulator secondary s-is electri- I provide switching means for 1 the regulator being so positioned cally at right angles toits primary 0, and

hence. no voltage is induced therem. Supposing for the moment that thevshorteircuiting switch 5 cuited secondary it lowers the reactance of the secondary 8 to a negligible value and hence the voltage impressed on the terminals m and n is the voltage between the terminal m and the tap 1., The connection from the terminal-n to the tap '1 it will be seen is through one-half of the secondary s, the lead a and the switch 1,; only one-half of the secondary therefore carries the entire load current. Since the regulator is doing no work, it may be short-circuited by means of the short circuiting switch 5, ashas been shown accomplished in Fig. 1. The sec 'ondary s now in parallel to the switch 5,

r and as a result carries practically no ourthe windings.

rent and is the source of no loss of energy.

Should it now be desired to change the voltage between the terminals m and 'n; the switch is first opened. The secondary, s is then turned about its axis and the voltage induced therein rises gradually from zero to its maximum, should its rotation be con tinued thus far; the maximum voltage is reached in the position illustrated in 2 when the secondary a is electrically parallel with the primary 6. The maximum voltage of the secondary s is by predesign substantially equal to the volta ebetween each pair of taps, and the secondary s is so wound and connecttd that its voltage is at every instant in the same direction as the voltage in the winding t, as has been indicated by the arrows in Fig. 2 which may represent the.

direction of the voltages at some instant. -With the secondary in this position, the voltage between the terminals m and n is equal to the voltage induced between the terminal m and a point electrically midway betweenthe taps 1 and 2; the half ofthe secondary Winding between its connection to the terminal n and the terminal a is'still carrying the full load current. Since, however, the voltage of the secondary s is equal and opposed to-the voltage between the terminals 1 and 2, the switch 2,, may be closed the only efi'ect being-to distribute the load current between the two halves of the secondary s.

Should it be desired to continue the varia it bccon'ies electrically perpendicular to the primary Prior to its continued rotation from the'position shown in Fig. 2,

the switch 1,, has been open to'prevent an interclmnge of current between the taps-i1 and 2 due to their constant ditlcrcnce oi p'otem tial and the decreasing. voltage induced in V /hen the secondary: again reaches a-pos'tion electrically perpendicuis open, the short-cirlar to its orin'iar e the short-circuitin:

switch (3 :nay lp-ecloreezl and all the appzn the regulator secondary s.

:fore the short-circuit1n trated in Fig. 1, with the exception that the terminal '12 is now connected direct to the tap- 2 rather than to the tap 1. A cycle of operations has been completed and this cycle may be repeated in either direction as de-. I

sired or required. 7

The short-circuiting switches 5 and 6 are particularly useful where it is necessary for are relatively long, a, smaller regulator than would otherwise sullice, may be used, since such a regulator will stand the overloadingrequired for the short transition periods, it being for the greater periods of operation shorteircuited by the short-circuiting switches. While the reduction in size may I not be so appreciable. where the regulator is required to remain in the position shown in Fig. 2 for more or less long periods the size of the re lator may be considerably reduced 'provi ing the transition periods to and from this positional-e short. The connection of the terminal a to'the'. electrical center point of the secondary s, also allows a considerable simplification of the switching device, which ordinarily comprises a. single structure, the various switching contacts operating in their proper order and at v the proper times relative to the position of For three-phase transformers, the poten .tial regula'tor is also to be built thre'chase- Each shortcircuit of the regulator 1n the positions equivalent to that shown in Fig.

1, must then contain resistance. This cf feet-is preferably obtained by using a'do'uble regulator, as shown in Fig. 3. The halves of the-secondary winding of the two portions'are connected; so that their electromotive forces are oppo'site' in direction be e of the corresponding phases. This 'dolibl'e potential regulater will at the same time serve, in the well known manner, to compensatefor the phase displacement produced by a single re lator. n Fig. 3 the reference characters-aresimr lar to those of the preceding figures, but the characters are furnished in addition-With numbers indicating thepliasjes to which the parts are related.

t t. t, are w ndings of a three-phase regulating transformer provided with taps.

- The primary windings .e-,', '0 e,- and e,",

(+ a f pf thotwoparts of the double regulator arc-here shown, by way of example,

connected star and connected, in -paralivlto the phases of cf cf ofv the rates is then in the same rclatioz'i as illus. i transformer. If the twoprimary windings' of .the double regulator are arranged on the two stationary members thereof in opposite directions, as shown, so that the rotating fields created by them rotate in opposite directions, then the corresponding secondary phase windings, which are connected in series with each other,-'-s, and s 8, and s s and s, respectively, create a resultant supplementary voltage, which, at every position of the rotating member of the double regulator, has the same phase angle as the corresponding phase cf cf of, of the transformer. This resultant supplementary voltage-will also pass through zero, and then the halves of the secondary winding of the double regulator may be short-circuited by the switches u u. u, and 0,, '0 0 respectively.

I have described one suitable arrangement of the primary windings of the two halves of the double regulator. Other arrange- -ments will readily suggestthemselves to those skilled in the art.

lVi-th my invention a smooth voltage regu lation may be obtained by simple switching operations. Sparking is avoided, since at the switch contacts neither a stationary potential difference exists nor one which is caused by the interruption of current. That is, the sum of the inductive voltages between a and b of each phase caused by the variation of the current distribution in the secondary windings in connecting or discon necting one of the ends a, b, is always equal to zero.

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. The combination with a regulating winding provided with taps and a terminal connected to one end of said winding, of an induction regulator, a second terminal connected to approximately the center of the secomlary winding of the induction regulator, switching means for connecting the ends of said secondary wind ing to said taps, and means for short-circuiting each half of the regulator secondary winding.

2. The combination "with polyphase regus latiug windings provided with taps, of a double induction regulator having the secondary windings of each phase connected in series and having the prin'inry windings so connected and related thereto as to produce opposing elcctromotive forces therein when the secondaries are turned ninety degrees electrically from the maximum buck or boost position, terminals connected to the sccondaries, and switching means to connect the ends of the secondaries to the "taps.

3. The combination with polyphase regulating windings provided with taps, of a double induction regulator having the secondary windings of each phase connected in series and the primary wlndings so connected and related thereto as to produce opposing electromotive forces therein when the secondaries are turned ninety degrees electrically from the maximum buck or boost position, terminals connected to the secondaries, and switching means to connect the ends of the secondaries to the taps and to short-circuit the group of secondary windings of each phase.

4. The combination with polyphase regulating windings provided with taps, of a double inductiomregulator having one secondary winding of each base divided into two'sections and a' secon secondary winding of the same phase connected-in series with and between the sections of the first mentioned secondary winding and having the primary windings so connected and related to the secondary winding as to produce opposing electromotive forces in the different secondaries of each phase when the secondaries are turned ninety degrees electrically rom the maximum buck or boost position, terminals connected to the mid points of the second mentioned secondary windings, and switching means to connect the ends of the secondaries to the taps.

5. The combination with polyphase regulating windings provided with. taps, of a double induction regulator having one seoondary winding of each phase divided into two sections and a second secondary winding of the same phase connected in series with and between the sections of the first secondary winding and having the primary windings so connected and related to the secondaries as to produce opposing electromotive forces in the difi'erent secondaries of each phase when the secondaries are turned: ninety degrees electrically from the maxi mum buck or boost position, mains connected to the midpoints of the second sec ondaries, and switching means to connect. 

